Insulation sheet structure and concrete sandwich wall panel assembly constructed therewith

ABSTRACT

An insulation sheet for concrete sandwich wall panels comprising a sheet base composed substantially of expanded cellular foam and having opposed base surfaces. Protrusions on rigid plastic inserts molded into the sheet base extend from each of the base surfaces. Each of the protrusions has a narrow waist into which concrete flows to anchor the concrete onto the sheet. Narrow ducts extend through the insulation sheet.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a continuation-in-part application ofapplication Ser. No. 10/965,049, filed Oct. 14, 2004 for INSULATIONSHEET STRUCTURE AND CONCRETE SANDWICH WALL PANEL ASSEMBLY CONSTRUCTEDTHEREWITH in the name of Peter Fleischhacker.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

REFERENCE TO A SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTINGCOMPACT DISK APPENDIX

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to building construction, moreparticularly, to pre-cast, insulated, concrete panels.

2. Description of the Related Art

Concrete sandwich wall panels are well known in the buildingconstruction art. They typically consist of an insulation layersandwiched between two concrete layers with ties extending through theinsulation layer and into the concrete layers to secure the three layerstogether. In one method of manufacturing, the first concrete layer ispoured in a horizontal form and the insulation is placed on theconcrete. Before the concrete sets, the ties are pushed throughpre-drilled holes in the insulation and into the concrete. The ties havesurface irregularities so that, after the concrete flows around the tiesand cures, a secure attachment is provided between the concrete andties. Finally, the second concrete layer is poured on the insulation.The concrete flows around the surface irregularities of the ties tosecure the layers together after the concrete cures.

The above-described method has a number of shortcomings. First, it isvery labor intensive because a large number of ties must be individuallyinstalled before the bottom concrete layer cures. Second, the purpose ofthe insulation is to minimize thermal transfer between the concretelayers. In order to minimize thermal transfer, the ties need to be poorheat conductors. However, because the ties support the weight of theconcrete, the embedded portions of the ties are steel or other metalalloy, which are very good heat conductors. Consequently, the portion ofthe ties that reside in the insulation layer needs to be poorconductors. This means that the ties cannot be of a single material,which adds complexity and cost to the manufacturing process. Third, theinsulation is composed of extruded polystyrene (XPS), which can only beextruded with a rectangular, board-like cross section, profiled crosssections are not possible. Although XPS is a very good insulator, itdoes not “breath”, that is, its vapor impermeability is too high, andwater vapor can be trapped within the building.

BRIEF SUMMARY OF THE INVENTION

An object of the present invention is to provide an insulation sheet forinsulated concrete panel assemblies that minimizes construction labor.

Another object is to provide an insulation sheet for insulated concretepanel assemblies that is vapor permeable.

A further object is to provide an insulation sheet for insulatedconcrete panel assemblies that can be manufactured at or close to thejob site.

The present invention is an insulation sheet for concrete sandwich wallpanels and comprises a sheet base composed substantially of expandedcellular foam and having opposed base surfaces, and a plurality ofprotrusions extending from each of the base surfaces to a distal surfaceaway from said base surface, each of the protrusions having across-sectional shape such that a width of the distal surface is greaterthan a width of the footprint.

A concrete panel employing the insulation sheet of the present inventionis made by pouring a first concrete layer into a horizontal form,pushing the insulation sheet into the concrete layer before the concretesets, and then pouring the second concrete layer onto the insulationsheet.

The insulation sheet of the present invention is composed of an expandedcellular foam (ECF), which can be molded with surface features and isgenerally vapor permeable. The insulation sheet has a base andprotrusions extending from both base surfaces. The protrusions have twoembodiments. In one embodiment, the protrusions are integral with thesheet base and are generally mushroom-shaped so that the concrete flowsaround and surrounds the protrusions so as to be anchored in theconcrete after it sets. The protrusions can be any shape, such ascircular and ring-shaped, although any shape or combinations thereof maybe employed. In the second embodiment, the protrusion are on insertsthat are embedded in the sheet base during molding. The protrusion has awaist into which the concrete flows, anchoring the concrete to thesheet.

In the first embodiment, so that stacked insulation sheets can slideeasily on one another, the surface area of the smallest protrusions isgreater than any area of the same shape between protrusions. This meansthat the protrusions of adjacent stacked sheets will slide on each otherrather than falling in between the protrusions. Optionally, in order tofacilitate sheets sliding on each other and pushing the sheet into thefirst concrete layer, the surface of the protrusions are rounded.

In the second embodiment, the protrusions are two parts of separatelyproduced inserts that are embedded in the sheet base. Each protrusionhas opposed notches that form a waist for concrete to flow into. Theinserts can be anchored into the sheet base in one of two ways. In thefirst, the sheet base material extends through holes in the insert whenthe sheet is being produced. In the second, anchor facings sandwich thesheet base therebetween.

Narrow ducts extend through the insulation sheet to allow air betweenthe first concrete layer and the insulation sheet to escape whilepushing the sheet into the concrete and to facilitate vapor permeabilityof the panel.

Other objects of the present invention will become apparent in light ofthe following drawings and detailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the nature and object of the presentinvention, reference is made to the accompanying drawings, wherein:

FIG. 1 is a prospective view of a concrete sandwich of the presentinvention;

FIG. 2 is a perspective view of a section of the insulation sheet of thepresent invention;

FIG. 3 is a top view of a section of the sheet of FIG. 2;

FIG. 4 is a cross-sectional view of the sheet of FIG. 3 along the line4-4;

FIG. 5 is a cross-sectional view of the concrete sandwich of FIG. 1;

FIG. 6 is an enlarged view of a portion of a protrusion;

FIG. 7 is a perspective view of an insert of the present invention;

FIG. 8 is a cross-sectional view of an insulation sheet of the presentinvention with the insert of FIG. 7;

FIG. 9 is a cross-sectional view of the concrete sandwich using theinsulation sheet of FIG. 8;

FIG. 10 is a perspective view of another insert of the presentinvention; and

FIG. 11 is a cross-sectional view of an insulation sheet of the presentinvention with the insert of FIG. 10.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is an insulation sheet for use in concretesandwich wall panels and a concrete sandwich wall panel assembly thatemploys the insulation sheet.

A concrete sandwich wall panel 10 of the present invention is shown inFIG. 1. The basic method of making the panel 10 is similar to that ofthe prior art. The first concrete layer 14 is poured to the desiredthickness in a horizontal form. This layer 14 is typically a structuralcomponent, that is, it bears the weight of other components. Theparameters of the first layer 14 are dependent upon the use to which thepanel 10 is being put and the strength needed. As a structuralcomponent, the thickness of the first layer 14 will typically be in therange of six to twelve inches. The layer 14 may also includere-enforcement bars as needed according to architectural specifications.

Before the concrete set, the insulation sheet 12 is pushed into theconcrete layer 14, as explained below. Then the second concrete layer 16is poured onto the insulation panel 12 in the desired thickness. Thesecond layer 16 is typically of a lighter weight aggregate about one tosix inches thick, again depending upon the use to which the panel 10 isput. Re-enforcement bars and/or wire mesh may be included according toarchitectural specifications. The concrete layers 14, 16 may besymmetrical, that is, both have the same thickness and composition, orasymmetrical, that is, different thicknesses and/or compositions. Thesurface finishes of the concrete layers 14, 16 depend on the use towhich the panel 10 is put.

The insulation sheet 12 of the present invention is composed of expandedcellular foam (ECF), rather than the extruded polystyrene (XPS) of theprior art. Examples of ECFs are expanded polystyrene (EPS), expandedpolypropylene (EPP), expanded polyethylene (EPE), and expandedcopolymers such as polystyrene/polyphenylene oxide and modifiedpolyphenylene oxide and polyphenylene ether. The density of the ECF willvary depending upon the application and will typically be in the rangeof from one to twelve pounds per cubic foot.

ECF is not restricted to a flat shape, as is XPS. ECF can be molded toinclude surface features. ECF has some vapor permeability so that watervapor is not trapped within the building. In other words, a panel 10made with the insulation sheet 12 of the present invention “breathes”.Additionally, a “shape-molding” installation is more easily available toa concrete pre-caster, either by in-house investment and in-houseproduction, or by tapping into one of hundreds of local ECF convertersthat already have ECF manufacturing know-how and an existing ECFinfrastructure. Long-term savings would be in either greatly reduced oreliminated costs associated with transporting XPS sheets from one of therelatively few number of supplier' plants around the country.

The insulation sheet of the present invention has two embodiments 12,112. Both embodiments have a sheet base 18, 118 and a plurality ofprotrusions 20 a, 20 b(collectively, 20), 120 extending from the basesurfaces 22, 24, 122, 124 of the sheet base 18, 118. The thickness ofthe base sheet 18, 118 will depend upon how much insulation is desiredand can typically be in the range of from one to twelve inches.

The difference between the two embodiments lies in the protrusions. Inthe first embodiment 12 of FIGS. 2-6, the protrusions 20 are integrallymolded as elements of the sheet 12. In other words, the sheet 12 isproduced in one step as a unitary construct. In the second embodiment112 of FIGS. 7-11, the protrusions 120 are two parts of separatelyproduced inserts 128 that are added to the sheet base 118 during themolding process. In other words, the sheet 112 is produced in two steps,where the inserts 128 are produced in the first step and the sheet base118 is molded around the inserts 128 in the second step.

In the first embodiment of the protrusions 20, the width of the distalsurface 26 of the protrusion 20 is generally larger than the width ofthe protrusion footprint 28, the area of the protrusion 20 at the basesurface 22, as shown in the cross-section of FIG. 4. In other words, theprotrusion cross-section is generally mushroom-shaped. The idea is that,when the sheet 12 is pushed into unset concrete, the concrete flowsaround and surrounds the protrusions 20, as at 30 in FIG. 5. When theconcrete sets, the protrusions 20 are anchored in the concrete. Withprotrusions extending from both base surfaces 22, 24, the concretelayers 14, 16 are interlocked via the insulation sheet 12, therebycreating an insulated concrete sandwich. The height of the protrusion 20and the angle 42 of the protrusion side wall 40 are dependent on thedensity of the ECF used for the insulation sheet 12 and to the weightand density of the concrete layers 14, 16. Consequently, theseparameters will vary according to the application. The protrusions 20can typically range in height from 1/2 inch to two inches and the sidewall angle 42 can typically range from one to ten degrees.

Because of the integral protrusions, there is no need to manually insertindividual ties, like the panels of the prior art. Consequently,manufacturing labor cost is greatly reduced.

FIGS. 2-5 show two different shapes for the protrusions 20: a ringprotrusion 20 a and a circular protrusion 20 b. These are merelyillustrative shapes and the present invention contemplates that anyprotrusion shape or combinations of protrusion shapes that have thecharacteristics described herein may be employed. For example, all theprotrusions can be circular or the protrusions can be other shapes, suchas squares and rectangles. The size of the protrusions can vary greatlydepending upon the application. The ring protrusions 20 acan be, forexample, three to ten inches in diameter and the circular protrusions 20b can be, for example, one to five inches in diameter.

Typically, the insulation sheets 12 are stacked for delivery to wherethe panels are manufactured. It is desirable that, as an insulationsheet 12 is needed for a panel 10, the sheet 12 be easily slid from thetop of the stacked sheets 12. Because the XPS insulation sheets of theprior art are flat, they can be slid off quite easily. The insulationsheet of the present invention solves this issue by using protrusions 20with a smallest distal surface area that is greater than any area of thesame shape between distal surfaces 26. For example, in FIG. 3, thesmallest protrusion 20 is circular and the distal surface diameter 34 isgreater than the largest circular space 36 between distal surfaces 26.This means that the distal surfaces 26 of protrusions 20 of adjacentsheets 12 will slide on each other rather than falling in between theprotrusions 20.

If the distal surfaces 26 are flat, slight irregularities in theprotrusions 20 may cause the protrusions 20 of adjacent sheets 12 tocatch each other when trying to slide one sheet 12 off a stack. To solvethis issue, the distal surface 26 of the protrusions 20 are optionallyrounded, as in FIG. 4. In the case of the ring protrusions 20 a, theprotrusion 20 a has a raised ridge in the center of the distal surface26 that is rounded to the two edges 36. In the case of the circularprotrusions 20 b, the protrusion 20 b is domed. The rounded distalsurface 26 facilitates sliding the sheets 12 along each other becausethe edges 38 of the protrusions 20 will not catch on each other.

Another advantage of the rounded distal surface 26 is that it is easierto push into the first concrete layer 14. The present inventioncontemplates other shapes for the distal surface, for example, pointed,that facilitate pushing the insulation sheet 12 into the concrete layer14.

In the second embodiment, the protrusions 120 are two parts ofseparately produced inserts 128. Two examples of inserts 128 of thepresent invention are shown in FIGS. 7-11. The insert 128 has anembedded section 134 and two protrusions 120. The embedded section 134is that part of the insert 128 that is embedded within the sheet base118. Consequently, the length of the embedded section 134 is the same asthe thickness of the sheet base 118.

The protrusions 120 extend from both ends of the embedded section 134.Each protrusion 120 has a distal surface 126 away from the embeddedsection 134 and a pair of opposed notches 142 that form a waist 140 thatis narrower than the distal surface 126. The idea is that, when thesheet 12 is pushed into unset concrete, the concrete flows into thewaist 140 and surrounds the protrusions 120, as at 130 in FIG. 9. Whenthe concrete sets, the protrusions 120 are anchored in the concrete.With protrusions 120 extending from both base surfaces 122, 124, theconcrete layers 14, 16 are interlocked via the insulation sheet 112,thereby creating an insulated concrete sandwich.

Because of the protrusions 120 are integral parts of the sheet 112 atthe construction site, there is no need to manually insert individualties, like the panels of the prior art. Consequently, manufacturinglabor cost is greatly reduced.

The parameters of the insert 128 (height, thickness, diameter, waistsize, etc.) depend upon the application, for example, the weight anddensity of the concrete layers 14, 16, and the material from which theinsert 128 is constructed. Obviously, the stronger the material is, thethinner the insert 128 can be while maintaining the same strength. Inaddition, because the sheet 112 is insulating, the insert material isexpected to have a low heat conductivity. Contemplated materials for theinserts 128 include materials that are of similar a similar chemicalcomposition as the sheet base 118, for example, polystyrene. Using asimilar chemical composition facilitates recycling. Other rigid,low-conducting materials are contemplated, such as other plastics andcarbon composites.

FIGS. 7 and 10 show two different shapes for the inserts 128: a basictwo-dimensional shape in FIG. 7 and the basic three-dimensional shape inFIG. 10. These are merely illustrative shapes and the present inventioncontemplates that any insert shape or combinations of insert shapes thathave the characteristics described herein may be employed. For example,all the inserts can be two-dimensional or the inserts can be othershapes.

The protrusion 20 the first embodiment optionally have rounded distalsurfaces 26 so that the sheet 12 can be more easily pushed into thefirst concrete layer 14. The protrusions 120 of the second embodimentare generally thin enough that there is no need to shape the distalsurface 126 to make it easier to push the sheet 112 into the firstconcrete layer 14, although for especially large protrusions 120 orheavy concrete it may be desirable to do so.

The present invention contemplates two basic ways of anchoring theinsert 128 in the sheet base 118, either of which can be used with anyinsert configuration. In the first anchor configuration, shown in FIGS.7-9, the embedded section 134 includes one or more holes 136 throughwhich the sheet base material extends, anchoring the insert 128 in thesheet base 118. The number and size of the holes 136 can depend on thesize of the inserts 128 and the thickness of the sheet base 118.

The second anchor configuration, shown in FIGS. 10 and 11, has an anchorface 138 at the base of each protrusion 120. The anchor faces 138 extendoutwardly from the embedded section 134 over the sheet base outersurfaces 122, 124 to sandwich the sheet base 118 therebetween.

The present invention contemplates that a sheet 12 may include bothprotrusions of the first embodiment and protrusions of the secondembodiment.

Narrow ducts 32, 132 extend through the sheet 12, 112 at variouslocations, providing two functions. First, they allow air between thefirst concrete layer 14 and the insulation sheet 12, 112 to escape whilepushing the sheet 12, 112 into the concrete, thereby reducing thepossibility of air bubble formation. Second, the ducts 32, 132facilitate vapor permeability of the final product. The ducts 32, 132are small enough so that concrete will not fill them. Because a thinnerconcrete mix would more easily fill larger ducts, the diameter of theducts 32, 132 is dependent on the viscosity and aggregate mix of theconcrete.

Thus it has been shown and described an insulation sheet and a concretesandwich assembly constructed therewith that satisfies the objects setforth above.

Since certain changes may be made in the present disclosure withoutdeparting from the scope of the present invention, it is intended thatall matter described in the foregoing specification and shown in theaccompanying drawings be interpreted as illustrative and not in alimiting sense.

1. An insulation sheet comprising: a) a sheet base composedsubstantially of expanded cellular foam and having opposed basesurfaces; b) a plurality of rigid inserts embedded in said sheet base;c) each of said inserts including an embedded section embedded in saidsheet base and protrusions extending away from said opposed basesurfaces; and d) each of said protrusions having a distal surface and awaist that is narrower than said distal surface.
 2. The insulation sheetof claim 1 wherein each of said inserts includes an anchor to retainsaid insert in said sheet base.
 3. The insulation sheet of claim 1wherein said sheet includes ducts that extend through said insulationsheet.
 4. The insulation sheet of claim 1 wherein said expanded cellularfoam is selected from the group consisting of expanded polystyrene,expanded polypropylene, expanded polyethylene, and expanded copolymers.5. An insulation sheet comprising: a) a sheet base composedsubstantially of expanded cellular foam and having opposed basesurfaces; b) a plurality of rigid inserts embedded in said sheet base;c) each of said inserts including an embedded section embedded in saidsheet base, an anchor to retain said insert in said sheet base, andprotrusions extending away from said opposed base surfaces; d) each ofsaid protrusions having a distal surface and a waist that is narrowerthan said distal surface; and e) said sheet including ducts that extendthrough said insulation sheet.
 6. The insulation sheet of claim 5wherein said expanded cellular foam is selected from the groupconsisting of expanded polystyrene, expanded polypropylene, expandedpolyethylene, and expanded copolymers.
 7. A concrete sandwich assemblycomprising a first concrete layer, a second concrete layer, and aninsulation sheet therebetween, said insulation layer comprising: a) asheet base composed substantially of expanded cellular foam and havingopposed base surfaces; b) a plurality of rigid inserts embedded in saidsheet base; c) each of said inserts including an embedded sectionembedded in said sheet base and protrusions extending away from saidopposed base surfaces; and d) each of said protrusions having a distalsurface and a waist that is narrower than said distal surface.
 8. Theinsulation sheet of claim 7 wherein said sheet includes ducts thatextend through said insulation sheet.
 9. The insulation sheet of claim 7wherein said expanded cellular foam is selected from the groupconsisting of expanded polystyrene, expanded polypropylene, expandedpolyethylene, and expanded copolymers.
 10. A method of constructing aconcrete sandwich assembly comprising the steps of: a) providing aninsulation sheet comprising a sheet base composed substantially ofexpanded cellular foam and having opposed base surfaces, a plurality ofrigid inserts embedded in said sheet base, each of said insertsincluding an embedded section embedded in said sheet base andprotrusions extending away from said opposed base surfaces, and each ofsaid protrusions having a distal surface and a waist that is narrowerthan said distal surface; b) pouring a first concrete layer into a form;c) pushing said protrusions of a first of said opposed base surfaces ofsaid insulation sheet into said first concrete layer; and d) pouring asecond concrete layer onto a second of said opposed base surfaces ofsaid insulation sheet.
 11. The method of claim 10 wherein said sheetincludes ducts that extend through said insulation sheet.
 12. The methodof claim 10 wherein said expanded cellular foam is selected from thegroup consisting of expanded polystyrene, expanded polypropylene,expanded polyethylene, and expanded copolymers.